Means for transporting particulate material



Feb. 13, 1968 w, R. MACMILLAN 3,368,667

MEANS FOR TRANSPORTING PARTICULATE MATERIAL Filed July 28, 1966 4 Sheets-Sheet 1 FIG.

FIG. 2.

Feb. 13, 1968 w. R. MACMILLAN MEANS FOR TRANSPORTING PARTICULATE MATERIAL 4 vSheets-Sheet 2 Filed July 28, 1966 Feb. 13, 1968 w. R. MACMILLAN 3,363,657-

MEANS FOR TRANSPORTING PARTICULATE MATERIAL Filed July 28, 1966 4 Sheets-Sheet :5

IOI

Feb. 13, 1968 w. R. MACMILLAN MEANS FOR TRANSPOR'IING PARTICULATE MATERIAL 4 Sheefs-Sheet 4 Filed July 28, 1966 United States Patent 3,368,667 MEANS FOR TRANSPORTING PARTICULATE MATERIAL William Robertson Macmillan, Sale, England, assignor to Tilghmans Limited, Cheshire, England, a British company Filed July 28, 1966, Ser. No. 568,462 Claims priority, application Great Britain, Sept. 16, 1965, 39,529/ 65 6 Claims. (Cl. '198--224) ABSTRACT OF THE DISCLOSURE An apparatus for conveying blasting shot in which an eccentrically driven grid located above a fixed floor supporting the shot is operative by successive arcuate sweeps relative to the floor to move the shot across the floor into a trough having a floor portion at or above the level of the fixed floor and from which trough the shot is discharged.

This invention relates to apparatus for conveying particulate material, for example abrasive material used in shot blasting processes or the like.

In shot blasting processes abrasive shot is normally projected at the article to be treated within a blasting chamber. The spent shot then falls to the floor of the chamber from where it has to be collected. This collection has previously been effected by providing collecting hoppers fitted beneath a perforated floor of the chamber which received the spent material through the perforated floor plates before transporting it to a discharge point for recycling or recovery treatment. The provision of such hoppers necessitated the formation of a deep pit below the floor of the blast room or chamber in order to accommodate the hopper mechanism.

An object of the present invention is to provide means whereby spent abrasive material can be collected from the floor of a blast chamber and transported to a discharge point without the necessity of providing such under-floor pits as have previously been required. 7

According to the present invention, there is provided apparatus for conveying particulate material comprising a fixed floor on to which the particulate material is adapted to rest, and an oscillatable grid located above said floor, the grid being adapted to be oscillated in order to contact material lying on the floor and to urge it along the floor to dis-charge.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIGURE 1 is a partially cut away plan view of apparatus for conveying particulate abrasive material according to the present invention.

FIGURE 2 is a sectional view along the line AA of the apparatus shown in FIGURE 1.

FIGURE 3 is an end view of the apparatus viewed from the direction of arrow C in FIGURE 1.

FIGURE 4 is a sectional view along the line B-B of the apparatus in FIGURE 1.

FIGURE 5 is a plan view of apparatus for conveying particulate abrasive material according to a second embodiment of the present invention.

FIGURE 6 is a sectional view along the line DD of the apparatus shown in FIGURE 5, and I FIGURE 7 is an end view of the apparatus viewed from the direction of arrow E in FIGURE 5.

Referring to FIGURES 1 to 4, the apparatus for conveying particulate abrasive material from the floor of a blasting chamber (not shown) comprises a fixed floor 8 set in a frame 9 formed of U-shaped channel girders with I-section channel girders 10 extending across the frame and secured by bolts thereto. A false floor, spaced above the fixed floor '8, is made up of three perforated plates 11, 12 and 13 secured to the upper flanges of the girders of the frame 9 and transverse girders 10. The false floor extends over the area enclosed by the frame 9.

Intermediate the fixed and false floors are three rectangular grids 14, 15 and 16 mounted side by side along the length of the apparatus just clear of the fixed floor 8. The grids 14, 15 and 16 are carried by bearings 17, four bearings per grid, mounted on a pair of longitudinally extending shafts 19 and 20 which are eccentrically mounted adjacent their extremities to opposing sides of the frame. The grids 14, 15 and 16 are arranged to be oscillated about a longitudinal axis on rotation of the shafts 19 and 20 by means of an electric motor shown schematically at 21, connected with the shafts through a sprocket wheel 22 keyed to the motor 21 carrying a chain 23 passing over a sprocket wheel 24 keyed to shaft 20. Shaft 19 has a sprocket wheel 25 attached thereto carrying a chain 26 passing over a second sprocket wheel 27 on shaft 20. A chain tensioner 28 contacts the chain 26 to keep it in constant tension.

The grids 14, 15 and 16 each consist of an outer frame having bars extending transversely thereacross and longtudinally therealong at spaced intervals (see FIGURE 1) and the bars being of an appreciable depth eg one inch.

Portions 18 of the grids 14, 15 and 16 are inclined upwardly at their forward ends relative to the direction of rotation of the shafts 1'9 and 20. An inclined plate 29 positioned parallel to and beneath the inclined portions 18 of the grids 14, 15 and 16 is attached to a longitudinally extending spacer 30 mounted between the fixed and false floors. The plate 29 extends longitudinally with the grids and is configurated to form a recess or trough 31 beyond the inclined portions 18- of the grids 14, 15 and 16. The end of the plate 29 remote from the inclined portions 18 is welded to the frame 9. A longitudinal scroll 32 extends along the recess or trough 31.

In operation of the apparatus, spent abrasive falls, from the basting chamber, through the perforations of the false floor to form a layer on the fixed floor. On rotation of the shafts and hence oscillation of the grid, the crossbars of the grid engage the layer of material on the fixed floor and urge it, during their travel through the lower part of their path of oscillation, forwardly towards the trough at the forward end of the grid. On the upper part of the oscillating path, each bar travels upwardly and away from the scroll clear of the layer of material before re-engaging fresh material urged by the adjacent bar in the direction of the scroll. In this way the grid moves the layer of material along the floor until it directs it into the trough where it is picked up by the scroll to be fed out of the machine into a collecting arrangement whereby the material can be recycled or otherwise treated.

In the second embodiment of the present invention, as illustrated in FIGURES 5 to 7, the apparatus for conveying particulate abrasive material comprises, as in the first embodiment, a fixed floor set in a frame 101 formed of U-channel girders, with I-channe1 girders 102 extending across the frame 101 and secured by bolts thereto. A false floor 103, spaced' above the fixed floor 100, is made of perforated plates (shown cut-away in FIGURE 5) and extends over the area enclosed by the frame 101 as in the previous embodiment.

However, in this embodiment, two sets of grids 106 and 107, are set on each side of a scroll 108, are mounted along the length of the apparatus and are carried by bearings 109, there being four bearings per grid. Each set of grids 106 and 107 is mounted by means of bearings 109 on a pair of longitudinally extending shafts 110, 111 and 112, 113, respectively, which are mounted adjacent their extremities to the frame 101 to rotate eccentrically. The sets of grids 106 and 107 are arranged to be oscillated about a longitudinal axis on rotation of the shafts 110 and 111 by means of an electric motor, shown schematically at 114. The drive from the electric motor 114 comprises a sprocket wheel keyed to the shaft thereof driving a chain 115 which passes around a sprocket wheel 116 mounted on shaft 111 outside the frame 101. A second sprocket wheel 117 on shaft drives the shaft 110 through a chain 18 and a sprocket wheel 119 keyed to shaft 110. The end of shaft 110 remote from sprocket wheel 119 is freely eccentrically rotatable in mounting 120 on frame 101.

A gear Wheel 121 is keyed to the end of shaft 111 remote from sprockets 116 and 117, which gear wheel 121 meshes with a second gear wheel 122 keyed to a shaft 123 which is freely rotatable in mountings 124 and 125 on the frame 101 and one of the I-channel girders 102, respectively. The shaft 123 also carries a sprocket wheel 126 which is connected through a chain 127 with a sprocket wheel 128 keyed to shaft 112. Shaft 113 has a sprocket wheel 129 keyed thereto which is connected with a sprocket wheel 130 on the end of shaft 112 remote from sprocket wheel 128 through a chain drive 131. Chain tensioners 132 are incorporated in all the chain and sprocket wheel mechanisms to keep the tension of the chain constant.

The sides of sets of grids 106 and 107 adjacent the scroll 108 are inclined upwardly towards the scroll 108 and a plate 133 (see FIGURE 6) is mounted under the inclined portions of the sets of grids 106 and 107. The plate 133 extends along the length of the apparatus and is configurated to form a-trough underneath the scroll 108. The plate 133 is secured to spacers 134 and 135 and to the fixed floor 100 along its length.

In operation of the apparatus, the motor 114 turns shafts 110 and 111 such that the set of grids 166 urges abrasive material towards the scroll 108. The shafts 112 and 113 are rotated in an opposite direction and cause the set of grids 107 to urge abrasive material towards the scroll 108 from the side of the scroll remote from the set of grids 106.

In the arrangements described above, the lowest point of the grid oscillating path is preferably arranged to give a minimum clearance of the grid over the fixed floor.

The amount of particulate material which can be collected at any time is governed by the frequency and amplitude of the oscillation of the grid. The arrangement is preferably such that the amplitude is equal to the pitch of the bars making up the grid, so that on each cycle the particulate material is moved forward by a distance equal to the pitch of the bars. It is therefore a simple matter to control the volume handled in unit time by adjusting the speed of rotation of the shafts, the bar pitch and the stroke of the grid.

It will be apparent that any number of grids may be used in the sets depending upon the size of the blasting chamber. The perforated false floor plate or plates protects the underlying grid in that no large pieces of material can penetrate the false floor to cause damage to or clog the grid.

By means of the present invention an arrangement for collecting spent abrasive particles from the floor of a blast chamber or the like is provided in which the mechanism is accommodated within a relatively shallow depth e.g. 8 inches, thereby dispensing with the requirement of a deep collecting pit below the chamber as has been necessary with previously proposed arrangements.

What I claim is:

1. Apparatus for conveying blasting shot comprising a frame containing a fixed floor for supporting said shot, said floor having a terminal end, a trough alongside said terminal end into which the shot is adapted to be discharged, said trough having a floor at least at the level of the fixed floor, at least one eccentrically drivable grid located above said fixed floor and profiled to mate with the latter floor, at least two mutually parallel eccentrically rotatable shafts spanning said frame and from which shafts the grid is suspended whereby the shot is moved across said fixed floor over the terminal end into the trough by successive arcuate sweeps of the grid.

2. The apparatus as claimed in claim 1 in which said terminal end is defined by an upwardly inclined portion with said grid having an upwardly inclined portion complementary thereto.

3. The apparatus as claimed in claim 2 in which said grid includes an outer frame, and bars extending transversely thereacross and longitudinally therealong at spaced intervals with the bars being of an appreciable depth.

4. The apparatus as claimed in claim 3, further including a false perforated floor located above the grid for preventing large shot adversely affecting the grid.

5. The apparatus as claimed in claim 2 further including a rotatable scroll within the trough whereby the shot moved into the trough by the grid is discharged.

6. The apparatus as claimed in claim 5 in which a grid is provided on each side of the scroll with each grid being oscillatable in such a way that the shot is urged towards the scroll.

References Cited UNITED STATES PATENTS 946,553 1/ 1910 Mitchell -l70 2,495,096 1/ 1950 Grimaldi 198224 2,593,123 4/1952 Dukas 198224 2,678,721 5/1954- Scott l98224 2,834,454 5/1958 Sambraus l98224 3,100,043 8/1963 Cordis l98224 ANDRES H. NIELSEN, Primary Examiner.

EVON C. BLUNK, Examiner.

R. J. HICKEY, Assistant Examiner. 

